equations Flashcards
Mathematical statement of the first law of
thermodynamics.
ΔE = q + w
Calculating work done in gas expansion or
gas compression
w = - P Δ V
Definition o[ enthalpy
H= E + PV
Calculating enthalpy (or energy) change for a constant-pressure rocess.
ΔH= ΔE + P Δ V
Definition of heat capacity.
C = ms
Calculating heat change in terms of specific heat
q = msΔt
Calculating heat change in terms of heat capacity
q = CΔt
Calculating standard enthalpy of reaction.
ΔH0rxn = ΣnΔH0f(products)- ΣmΔH0f (reactants)
Lattice energy and hydration contributions to heat
of solution.
ΔHsoln = U +ΔHhydr
Energy
Energy is the capacity to do work. There are many
forms of energy and they are interconvertible. The law
of conservation of energy states that the total amount of energy in the universe is constant
exothermic process
A process that gives off heat to the surroundings is exothermic
endothemic process
a process that absorbs heat from the surroundings
is endothemic.
state functions.
The state of a system is defined by properties such as
composition, volume, temperature, and pressure. These
properties are called state functions.
The change in a state function for a system depends on:
The change in a state function for a system depends
only on the initial and flnal states of the system, and not
on the path by which the change is accomplished. Energy is a state function; work and heat are not
first law of themodynamics
Energy can be converled from one form to another, but it
cannot be created or destroyed (first law of themodynamics).
In chemistry we are concerned mainly with thermal
energy, electrical energy, and mechanical energy, which
is usually associated with pressure-volume work.
